Here is a little nice task to put in your /lib/capistrano/tasks folder. This will allow you to run any rake task on the server.

desc "Run rake task on server"
task :sake do
on roles(:app), in: :sequence, wait: 5 do
within release_path do
as :deploy do
with rails_env: :production do
execute :rake, ENV['task'], "RAILS_ENV=production"
end
end
end
end
end